Children with developmental disabilities who received early intervention services before age 3 were more likely to meet third-grade academic standards in math and English language arts, according to a study published this month in JAMA Network Open. The research, conducted by Columbia University Mailman School of Public Health and the New York City Health Department, analyzed data from over 214,000 children born in New York City between 1994 and 1998.

The findings provide evidence that Part C of the Individuals with Disabilities Education Act (IDEA) services produce measurable academic benefits years after a child ages out of the program at three. Benefits were particularly strong for Latino/a children, families with lower socioeconomic status, and children who later required special education services.

What the Study Found

Researchers linked public health and education records for 214,370 children who had third-grade test data. Of these, 13,022 children (6 percent) received early intervention services before age 3.

Children who received early intervention showed higher absolute test scores in English language arts and were more likely to meet test-based standards in both math and ELA. Specifically, the study found an 8% improvement in the likelihood of meeting math standards and a 9% improvement in meeting ELA standards when comparing matched samples.

The academic benefits weren't uniform across all groups. Children who later required special education, those from households with lower socioeconomic status, and those born to immigrant mothers showed greater test score improvements associated with early intervention.

Why This Matters for Families

Few studies have examined the long-term academic impact of early intervention services provided under Part C IDEA, the federal grant program that helps states implement services for infants and toddlers with developmental delays and disabilities. Most research on early intervention has focused on targeted developmental outcomes in the short term.

This study demonstrates that the benefits extend beyond immediate developmental gains. Children who received speech, occupational, physical, or behavioral therapy before age 3 showed measurable academic improvements years later.

The timing matters. Part C services end when a child turns 3, at which point Part B of IDEA takes over for preschool-age children. This study suggests that what happens in those first three years has lasting effects.

What Part C IDEA Services Cover

Part C of IDEA is the federal law guaranteeing early intervention services to children from birth through age 2. Each state sets its own thresholds for "developmental delay," most requiring a score significantly below age norms, often between 25 and 33 percent.

Generally, a developmental delay is when an infant or toddler develops or matures at a slower rate than other children their age in communication skills, physical development, cognitive function, adaptive skills, or social or emotional development.

In 2023, approximately 463,000 infants and toddlers with disabilities received early intervention services under Part C of IDEA. Services are provided in the child's natural environment when possible and coordinated through an Individualized Family Service Plan (IFSP).

What Families Can Do Now

If you suspect your child has a developmental delay, you can request a developmental screening at no cost. Contact your state's early intervention program directly; you don't need a doctor's referral in most states.

The evaluation process typically includes:

• A comprehensive assessment of your child's development across multiple domains
• A family assessment to identify strengths and needs
• An IFSP meeting to determine eligibility and design a service plan if your child qualifies

Services are provided at no cost to families in most states, though some states charge fees on a sliding scale based on income.

Current Policy Context

This research comes as federal disability funding faces renewed scrutiny. The Trump administration's FY 2027 budget proposal maintains Part C Early Intervention Services at $209 million, level funding from the previous year. However, the FY 2026 budget proposed consolidating seven IDEA programs into a "Special Education Simplified Funding Program," which would grant the administration more discretion over how Part C, Part B, and Part D funds are distributed.

Congress rejected the consolidation plan and largely flat-funded IDEA programs on a bipartisan basis. Still, the debate signals ongoing pressure on federal special education funding at a time when this study provides new evidence of the program's long-term value.

Where to Find More Information

The full study is available on the JAMA Network Open website. A companion commentary, "Early Intervention and Children's Academic Outcomes: Why Part C Matters," is also available.

To find your state's early intervention program, visit the ECTA Center's state contact directory. If your child is approaching age 3 and currently receives Part C services, ask your service coordinator about the transition to Part B preschool services at least six months before your child's third birthday.